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Manufacturers are increasingly using encapsulated coal ash from power plants as a low-cost binding agent in concrete, wallboard, bricks, roofing and other building materials. But a new study by U.S. and Chinese scientists cautions that coal ash from high-uranium deposits in China may be too radioactive for this use.

Manufacturers are increasingly using encapsulated coal ash from power plants as a low-cost binding agent in concrete, wallboard, bricks, roofing and other building materials. But a new study by U.S. and Chinese scientists cautions that coal ash from high-uranium deposits in China may be too radioactive for this use.

“While most coals in China and the U.S. have typically low uranium concentrations, in some areas in China we have identified coals with high uranium content,” said Avner Vengosh, professor of geochemistry and water quality at Duke University’s Nicholas School of the Environment. “Combustion of these coals leaves behind the uranium and radium and generates coal ash with very high levels of radiation.”

The level of radiation in this coal ash could pose human health risks, particularly if it is recycled for use in residential building materials, he said.

Some of the coal ash samples analyzed in the new study contained radiation levels more than 43 times higher than the maximum safe limit established for residential building materials by the United Nations Scientific Committee on the Effects of Atomic Radiation.

Image: Coal ash from China’s high-uranium coal deposits, such as what is produced by this power plant, is too radioactive to be reused in building materials, a new study shows. (Image Credit: Shifeng Dai)